Load case sets (margin of safety)

Load case sets are sets of individual load and constraint combinations. The individual load and constraint combinations are referred to as load cases. Each load case is equivalent to a subcase in the linear static solution. Load case sets are listed in the Simulation Navigator under the Load Case Sets node.

When the linear static solution has global constraints, you can also create load case sets from combined load cases, which are linear combinations of subcases. For more information, see Combined load cases and Results for combined load cases.

When the software performs a calculation for margin of safety solutions, it repeats each margin of safety calculation in the solution for each load case in the load case set. That is, the software does not superpose the results from each load case set into a single result. Thus, for a given calculation, multiple margin of safety results may exist. For additional information, see Margin of safety calculations.

Example: Load case sets from subcases in margin of safety calculations

Suppose you want to evaluate the margin of safety for an aircraft wing against the following loads and combination of loads:

• Pressure distribution over the surface of the wing

• Weight of the fuel stored in the wing

• Forces that arise from control surface actuators

• Pressure distribution over the surface of the wing and weight of the fuel stored in the wing

• Weight of the fuel stored in the wing and forces that arise from control surface actuators

The number of subcases you need in the linear static solution depends on whether the constraints are the same for each loading.

• When the constraints are the same for each loading and you select SOL 101 Linear Statics - Global Constraints as the solution type, you can obtain the required results from three subcases:A subcase that accounts for the pressure distribution over the surface of the wingA subcase that accounts for the weight of the fuel stored in the wingA subcase that accounts for forces that arise from control surface actuatorsTo account for the two combinations of loadings, you can create combined load cases.

• When the constraints differ or you select SOL 101 Linear Statics - Subcase Constraints as the solution type, however, you must create a subcase for each of the five loadings.

Example: Load case sets in margin of safety calculations

The number of load case sets you create and the combinations of load cases that you include in each load case set depends on the results you want to obtain from the margin of safety calculation.

For example, suppose you want to calculate margin of safety for the following load case and calculation combinations:

• Yielding at the root of a groove in structural member against all five load cases

• Shearing of a fastener that joins two structural members against the forces that arise from the weight of the fuel

• Buckling of a structural member against the forces that arise from the weight of the fuel and the forces that arise from control surface actuators

To satisfy these requirements, you need to create three load case sets:

• A load case set that accounts for all five load cases

• A load case set that contains only the forces that arise from the weight of the fuel

• A load case set that includes the forces that arise from the weight of the fuel and the forces that arise from control surface actuators

Where do I find it?

Application	Pre/Post
Prerequisite	An active margin of safety solution
Simulation Navigator	Expand the margin of safety solution node→right-click Load Case Sets→Add Load Case Set

How do I

Create a combined load case

Modify combined load cases in a dialog box

Modify combined load cases in a spreadsheet or text editor

Create a load case set for a margin of safety calculation

Create a load case set from margin of safety results

Learn more

Combined load cases

Results for combined load cases

Exporting and importing load case sets (margin of safety)

Orphan load cases (margin of safety)

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Load case sets (margin of safety), Simcenter 3D 2021.1 Series

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